/*
 * Copyright 2011 Clean GWT
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.cleangwt.user.shared;

import java.util.List;

/**
 * This class provides methods for manipulating {@link Option}s.
 * 
 * @author Jess
 * @version 1.0
 * @since 1.0
 */
public class Options {
  public static final String FORM_DELIMITER = ", ";

  /**
   * Packs up value into a form with {@link #FORM_DELIMITER}.
   * 
   * The output would be 'value1, value2, value3, ...'.
   * 
   * @param value the value to pack up
   * @return
   */
  public static String form(List<String> value) {
    if (value == null || value.isEmpty()) {
      return null;
    }
    StringBuilder sb = new StringBuilder();
    for (String v : value) {
      sb.append(v).append(FORM_DELIMITER);
    }
    // remove last 2 chars ', '
    sb.deleteCharAt(sb.length() - 1);
    sb.deleteCharAt(sb.length() - 1);
    return sb.toString();
  }

  /**
   * Parses the given form value into tokens by {@link #FORM_DELIMITER}.
   * 
   * The form value should be 'value1, value2, value3, ...'.
   * 
   * @param formValue the form value to parse
   * @return the tokens
   */
  public static String[] unform(String formValue) {
    if (formValue == null || formValue.isEmpty()) {
      return null;
    }
    return formValue.split(FORM_DELIMITER);
  }
}
